Aircraft having variable sweep-back wings

ABSTRACT

A wing pivot assembly for an aircraft with variable-sweep-back wings, which comprises a pair of lugs secured to a wing and a cooperating pair of apertured lugs secured to the fuselage of the aircraft, the fuselage lugs lying between and close to the wing lugs. Both pairs of lugs are formed with coaxial central apertures, and the outer portions of the adjacent lugs are formed with opposed circular grooves coaxially surrounding the apertures, in which grooves are housed bearing rollers by which the upper wing lug is journalled on the upper fuselage lug, and the lower wing lug is journalled on the lower fuselage lug. The grooves may either be of trapezoidal section, for use with tapering rollers, or they may be of V-section for use with cylindrical rollers whose axes are radial and are inclined in alternately-opposed directions. A clamping device in the form of a pair of flanged rings whose outer flanges are engaged with the two wing lugs, the rings being drawn together by a nut-and-bolt device at their adjacent inner flanges to apply an axial clamping thrust to the pivot assembly.

ilnited States Patent [191 Ransom [54] AIRCRAFT HAVING VARIABLESWEEP-BACK WINGS [75] Inventor: Stephen Ransom, Saint Annes-On- Sea,Lancashire, England [73] Assignee: British Aircraft Corporation Limited,London, England Filed: Mar. 3, 1970 App1.No.: 24,414

[30] Foreign Application Priority Data Mar. 7, 1969 Great Britain..12,302/69 [52] 11.8. C1 ..244/46 [51] Int. Cl ...B64c 3/40 [58] Fieldof Search ..244/46; 308/244,

[56] References Cited UNITED STATES PATENTS 2,683,574 7/1954 Peterson..244/46 2,794,608 6/1957 Johnson ..244/46 3,018,985 1/1962 3,023,9843/1962 3,023,983 3/1962 11] 3,734,430 51 May 22, 1973 PrimaryExaminer-Robert F. Stahl Att0mey-Cushman, Darby & Cushman [5 7 ABSTRACTA wing pivot assembly for an aircraft with variablesweep-back wings,which comprises a pair of lugs secured to a wing and a cooperating pairof apertured lugs secured to the fuselage of the aircraft, the fuselagelugs lying between and close to the wing lugs. Both pairs of lugs areformed with coaxial central apertures, and the outer portions of theadjacent lugs are formed with opposed circular grooves coaxiallysurrounding the apertures, in which grooves are housed bearing rollersby which the upper wing lug is journalled on the upper fuselage lug, andthe lower wing lug is journalled on the lower fuselage lug. The groovesmay either be of trapezoidal section, for use with tapering rollers, orthey may be of V-section for use with cylindrical rollers whose axes areradial and are inclined in alternately-opposed directions. A clampingdevice in the form of a pair of flanged rings whose outer flanges areengaged with the two wing lugs, the rings being drawn together by anut-and-bolt device at their adjacent inner flanges to apply an axialclamping thrust to the pivot assembly.

7 Claims, 5 Drawing Figures Patented May 22, 1973 I 3,734,430

3 Sheets-Sheet 1 INVENTOR S'rePnw RAN-8cm BYCU-S/IM4A6 baggy CMQHMAI/ATTORNEY-S 3 Sheets-Sheet 2 ATTORNEY$ AIRCRAFT HAVING VARIABLESWEEP-BACK WINGS The present invention relates to aircraft havingvariable sweep-back wings, in which the wings pivot in relation to thefuselage about substantially vertical axes to alter their angle ofsweep-back.

In this specification the term vertical is used to mean the direction,in relation to the aircaft, which is vertical in normal unbanked levelflight.

According to the invention, an aircraft wing pivot assembly comprises apair of vertically-spaced apertured lugs forming part of the fuselagestructure, a further pair of vertically-spaced apertured lugs formingpart of the wing structure, one of the pairs of lugs (referred to as theinner pair) lying in between the other pair (re ferred to as the outerpair), the upper lugs of both pairs being provided with opposed tracksbetween which an upper, circularly disposed, series of bearing elementsare located and the lower lugs of both pairs being similarly providedwith opposed tracks between which a lower, circularly disposed, seriesof bearing elements are located, and the outer pair of lugs beingprovided with a clamping means extending through the apertures of allfour lugs and acting between the lugs of the outer pair to urge themtoward each other and toward the inner pair of lugs to maintain the twoseries of bearing elements in close contact with their respectivetracks.

The tracks for each of the two series of bearing elements may compriseopposed circular grooves formed in the facing surfaces of the adjacentlugs.

The grooves may be generally trapezoidal in crosssection in which casethe bearing elements of each series comprise tapered rollers spaced onefrom another with their axes radially disposed with respect to thegrooves by means of an annular cage having rollerreceiving slots atspaced intervals around its periphery.

Alternatively, the grooves may be V-shaped in crosssection, in whichcase the bearing elements of each series comprise rollers separated onefrom another by disc-like spacers, and the rollers have their axesdisposed in planes which are substantially radial with respect to thegrooves, and adjacent rollers have their axes inclined oneto another sothat successive rollers are in rolling contact with alternate sides ofeach V- section groove.

The invention may be carried into practice in various ways but twospecific embodiments will now be described by way of example only withreference to the accompanying drawings, in which:

FIG. 1 is a plan view of an aircraft,

FIG. 2 is a part-sectional view of a wing pivot assembly, the sectionbeing taken through the substantially vertical major axis of the pivot,as indicated by the line Il--II of FIG. 1,

FIG. 3 is a similar view of an alternative form of wing pivot assemblyto that of FIG. 2,

FIG. 4 illustrates a method of caging the bearing elements of theassembly of FIG. 2, and

FIG. 5 illustrates the bearing elements of the assembly of FIG. 3.

Referring initially to FIG. 1, an aircraft has a fuselage 1 and variablesweep-back wings 2 and 3 which respectively pivot about substantiallyvertical axes XX on wing pivot assemblies 4 and 5. The wing pivotassemblies 4 and 5 are identical in all major aspects and for clarityonly one, namely that referenced 4, will now be fully described.

Referring now to FIG. 2, the fuselage 1 is provided with a pair ofvertically-spaced lugs 10,11 each having an aperture, 12,13respectively, formed concentrically therein. The lugs l0, 11 are spacedapart by an integral web 14 which is substantially cylindrical.

The root of the wing 2 is also provided with a pair of spaced lugs 15,16 each having an aperture, 17, 18 respectively, formed concentricallytherein. The lugs 15 and 16 are spaced apart by an integral web 19 beingpart of the wing structure. The apertures 12, 13 and 17, 18 areconcentric with one another and are effectively formed about asubstantially vertical axis XX which is the major axis of the wing pivotassembly and about which the wing 2 rotates.

The upper lugs 10 and 15 of each pair of lugs, as shown in FIG. 2, areclosely adjacent to one another and are separated by an upper series ofbearing elements. The bearing elements are, in this embodiment, taperedrollers 20 which are constrained to roll on tracks formed by the bottomsof opposed trapezoidallycross-sectioned circular grooves 21, 22 formedin the adjacent faces of the upper lugs 10 and 15, respectively. Thegrooves 21, 22 form together in effect a circular track the axis ofwhich is coincident with the axis XX.

The individual rollers 20 forming the series of hearing elements arespaced by an annular cage 23, see especially FIG. 4, which also aidsinsertion of the rollers into the track in a manner to be described. Thecage 23 has roller receiving slots 23a at spaced intervals around itsperiphery.

The lower lugs 11 and 16 of each pair of lugs, as shown in FIG. 2, areagain closely adjacent one another and are provided with a similarseries of rollers 20 constrained in a similar manner to the upper seriesof rollers.

In both the upper and lower series of rollers the rollers 20 may haveslightly convex part-spherical outer end faces 20a and theirco-operating faces, that is to say the outer sides of the grooves 21, 22are then formed in a slightly concave manner.

The wing pivot assembly is held together by a clamp extending throughthe apertures 12, 13 and 17, 18 and comprising two hollow frusto-conicalmembers 24, 25 each having an external flange 24a, 250, at its end oflarger diameter arranged to respectively engage the lug 15 and the lug16, and an internal flange 24b, 25b at its end of smaller diameter, theflanges 24b and 25b being drawn together at 26 by means of a tubular nut29. This arrangement has the advantage that on tightening a uniform loadis applied at all points around the flanges.

As the nut 29 and the bolt 28 are screwed together and the members 24and 25 are drawn together, the upper and lower lugs 15, 16 are drawntowards each other and towards the adjacent lugs 10, 11. Thus thebearing elements of each series are maintained in close contact withtheir respective tracks.

The flanges 24b, 25b may have a shim or shims 27 placed between them sothat the inward load applied to the lugs 15, 16 can be accuratelypre-determined. This load is reacted by the web 14.

The insertion of the rollers 20 into each track 21, 22 is effected bymeans of two radially extending apertures (not shown) respectivelyformed in the adjacent faces of the lugs l0, l5 and 11, 16 and leadinginto each track 21, 22. Each aperture is of such dimensions that aroller can be inserted therethrough, but since the aperture must be inthe same horizontal plane as the track 21 or 22 into which it feeds theaperture is partly formed in one lug and partly in another, so thatinsertion or removal can only be achieved when the parts of the apertureare in register, that is to say at one angular position of the wing withrespect to the fuselage.

Initially the wing lugs 15, 16 and the fuselage lugs 10, 11 arepositioned so that their grooves 21, 22 cooperate to provide the bearingtracks. The cages 23 are then inserted and the wing lugs are angularlymoved until the roller insertion apertures are in register with oneanother. Each cage 23 is then rotated until one of its roller receivingslots 23a is in register with the roller insertion aperture, whereupon aroller can be inserted into the track 21, 22. Rotation of the cage 23allows successive slots 23a to be presented to accept successivelyintroduced rollers 20 until the tracks are completely filled withrollers. The roller insertion apertures are each then filled with aspecially machinedl split plug (not shown) the split portions of whichare anchored to respective adjacent faces of the lugs enclosing therollers.

Referring now to FIGS. 3 and 5, which together illustrate anotherembodiment of the invention and in which like components are allottedlike reference numerals to those of FIG. 2, it can be seen that thetapered rollers 20 of the earlier Figure are replaced by cylindricalrollers 30. These rollers are incorporated in the wing pivot between thesame components as the rollers of the earlier Figure, namely the upperlugs 10, and the lower lugs 11, 16. Circular tracks in the rollers 30are formed by opposed grooves 31, 32 concentrically formed in theadjacent faces of the upper and lower lugs. Purely as an aid tomanufacture, the track surfaces with which the rollers co-operate areformed separately as rings of hardened material, for example a suitablesteel, and are inserted in the grooves 31, 32. Those engaging with thelugs 15, 16 are referenced 33, 34 whilst those engaging with the lugs10, 11 are referenced 37. As a further aid to manufacture and to providefor insertion of the bearing elements, each of the lugs 15, 16 is splitvertically along the center line of its groove 32 so that each such lughas a removable inner ring 150, 160 respectively. The rings 37 compriseV cross-sectioned rings which may be provided with packing shims 38 toposition the surfaces correctly with respect to their respective lugs10,11.

As shown in FIG. 3, the bearing grooves 31, 32 are each V-shaped incross-section. The arrangement of the bearing elements within thegrooves is shown particularly in FIG. 5. Each roller 30 has its majoraxis positioned in a radial plane which intersects the major axis XX ofthe pivot, but alternate rollers have their axes inclined at 45 and 135to the axis XX. Thus adjacent rollers have their axes inclined at 90 toeach 4 rollers 30. The rollers 30 may have rolling surfaces which areconvex in axial section, and part-spherical convex end faces, in whichcase the co-operating side walls of the grooves 31, 32 would be formedin a concave manner.

Shear loads on the wing pivot assembly may be transmitted in knownmanner from the wing to the fuselage by a bracket 35 mounted on the wingwhich cooperates with bearing pads 36 of low friction material mountedon the fuselage lugs 10, 11.

The insertion of the rollers 30 and the spacer discs 39 is effectedthrough the annular gap formed when the lugs 15, 16 and 10, 11 areassembled with the rings 15a and 16a not in position. When the rollers30 and spacer discs 39 are all inserted, the rings 15a and 16a arepositioned and clamped by the members 24, 25 and the nut and boltarrangement 28, 29 as described with respect to FIG. 2.

The grooves 21, 22 of the pivot assembly of FIG. 2 may be provided withseparate bearing surfaces on members similar to those provided(referenced 33, 34 and 37, 38) in the grooves 31, 32 of FIG. 3, but of across-section suitable for engagement by the tapered rollers 20.

What we claim as our invention and desire to secure by Letters Patentis:

1 An aircraft wing pivot assembly comprising a pair of vertically-spacedapertured lugs forming part of a fuselage structure, a further pair ofvertically-spaced apertured lugs forming part of a wing structure, oneof the pairs of lugs (referred to as the inner pair) lying in betweenthe other pair (referred to as the outer pair), the upper lugs of bothpairs being provided with opposed tracks between which an upper,circularly disposed, series of bearing elements are located, and thelower lugs of both pairs being provided with opposed tracks betweenwhich a lower, circularly disposed, series of bearing elements arelocated, and the outer pair of lugs being provided with a clamping meansextending through the apertures of all four lugs and acting between thelugs of the outer pair to urge them toward each other and toward theinner pair of lugs to maintain the two series of bearing elements inclose contact with their respective tracks.

2. An aircraft wing pivot assembly according to claim 1 in which thetracks for each series of bearing elements comprise opposed circulargrooves formed in the facing surfaces of the adjacent lugs.

3. An aircraft wing pivot assembly according to claim 2 wherein thegrooves are generally trapezoidal in cross-section and the bearingelements of each series comprise tapered rollers spaced one from anotherwith their axes radially disposed with respect to the grooves by meansof an annular cage having roller-receiving slots at spaced intervalsaround its periphery.

4. An aircraft wing pivot assembly according to claim 2 wherein thegrooves are V-shaped in cross-section and the bearing elements of eachseries comprise rollers separated one from another by disc-like spacers,the rollers having their axes disposed in planes which are substantiallyradial with respect to the grooves, and adjacent rollers having theiraxes inclined one to another so that the successive rollers are inrolling contact with alternate sides of each V-section groove.

5. An aircraft wing pivot assembly according to claim 1 wherein theclamping means comprises two hollow frusto-conical members, havingexternal flanges at structure and the outer pair of lugs forms part of awing structure.

7. An aircraft wing pivot assembly according to claim 1 in which theinner pair of lugs has surfaces engaged by opposed bearing pads carriedon a bracket in structural association with the outer pair of lugs.

1. An aircraft wing pivot assembly comprising a pair ofvertically-spaced apertured lugs forming part of a fuselage structure, afurther pair of vertically-spaced apertured lugs forming part of a wingstructure, one of the pairs of lugs (referred to as the inner pair)lying in between the other pair (referred to as the outer pair), theupper lugs of both pairs being provided with opposed tracks betweenwhich an upper, circularly disposed, series of bearing elements arelocated, and the lower lugs of both pairs being provided with opposedtracks between which a lower, circularly disposed, series of bearingelements are located, and the outer pair of lugs being provided with aclamping means extending through the apertures of all four lugs andacting between the lugs of the outer pair to urge them toward each otherand toward the inner pair of lugs to maintain the two series of bearingelements in close contact with their respective tracks.
 2. An aircraftwing pivot assembly according to claim 1 in which the tracks for eachseries of bearing elements comprise opposed circular grooves formed inthe facing surfaces of the adjacent lugs.
 3. An aircraft wing pivotassembly according to claim 2 wherein the grooves are generallytrapezoidal in cross-section and the bearing elements of each seriescomprise tapered rollers spaced one from another with their axesradially disposed with respect to the grooves by means of an annularcage having roller-receiving slots at spaced intervals around itsperiphery.
 4. An aircraft wing pivot assembly according to claim 2wherein the grooves are V-shaped in cross-section and the bearingelements of each series comprise rollers separated one from another bydisc-like spacers, the rollers having their axes disposed in planeswhich are substantially radial with respect to the grooves, and adjacentrollers having their axes inclined one to another so that the successiverollers are in rolling contact with alternate sides of each V-sectiongroove.
 5. An aircraft wing pivot assembly according to claim 1 whereinthe clamping means comprises two hollow frusto-conical members, havingexternal flanges at their ends of larger diameter and having internalflanges at their ends of smaller diameter, the external flanges beingengaged respectively with the outer pair of lugs and the internalflanges being drawn together by a screw threaded connection.
 6. Anaircraft wing pivot assembly according to claim 1 in which the innerpair of lugs forms part of a fuselage structure and the outer pair oflugs forms part of a wing structure.
 7. An aircraft wing pivot assemblyaccording to claim 1 in Which the inner pair of lugs has surfacesengaged by opposed bearing pads carried on a bracket in structuralassociation with the outer pair of lugs.